U.S. Pat. No. 5,163,816 Goetzke et al. describes engine turbocharger assemblies having novel arrangements for mounting a compressor impeller wheel on a shaft connecting with a turbine wheel for use in a turbocharger or the like. In FIG. 1 of this patent, a turbocharger arrangement is shown in which the turbine wheel is formed as part of the shaft on which the impeller wheel is mounted and a gear-driven drive shaft is connected with the turbine wheel through a plurality of bolts spaced around a hub and flange connection in known manner. The multiple bolted connection complicates the assembly and disassembly of the turbocharger, as well as requiring rebalancing of the assembly when turbocharger rotors are reassembled.